As testimony to the effectiveness of warning other motorists of new and beginning drivers, driver education vehicles have long been equipped with caution signs. Typically, these are large signs that mount permanently or almost permanently either on top or on the front and/or rear of the educational vehicle. However, graduation from a driver education class does not an experienced driver make. Typically, a neophyte driver remains such for many months if not longer. But, individuals do not usually want to permanently mount a caution of “new driver” to a family or personally owned and driven vehicle, especially if an experienced driver is usually at the wheel. Consequently, other devices have been proposed for use on personal automobiles. Some such caution devices are stick-on, a fact that deters many from use, as many automobile owners object to stickers on their cars for several reasons. Some devices provide lighted caution, which is also undesirable to some and also adds expense and need of service. Some automotive display devices are entirely of magnetic sheet. Such devices have proven prone to adhesion failure due to lack of conformity to anything but a continuously flat surface. The present apparatus provides a uniquely inverted triangle that can be magnetically temporarily mounted or mounted via restriction within an opening such as a hood or trunk, then removed at any time with no real effort.